Problem with Rotel Power Amp RB-1090

[TAYFUR GUNAY]

Dear Rotel lovers
I have a problem with my power amp RB-1090. When I press the front power up button all house lights go off. This problem happens as soon as i press the front button , before front leds light or soft start relay reacts. What would be the problem. I have experienced this problem one night i think, when voltage was about 250 or above (which should be 220)

After measuring certain points nothing wrong with internal parts.
Already changed the two diodes right after the mains, but problems still there.
Could be a problem with soft start relay or otherwise . I highly appreciate your assistance if similar case reported/experienced before.
Many thanks for your valuable guidance in advance.

[TAYFUR GUNAY]

Problem with Rotel Power Amp RB-1090

Dear Rotel Club Members,

Needing expert guidance for my power amp RB-1090, if possible.

When I press the front power up button all house lights go off. This problem happens as soon as i press the front button , before front leds light or soft start relay reacts. What would be the problem. I have experienced this problem one night i think, when voltage was about 250 or above (which should be 220vac)

After measuring certain points nothing wrong with internal parts. Already replaced the two diodes right after the mains, but problems still there.
Could be a problem with soft start relay or otherwise . I highly appreciate any assistance from whom experienced similar before...Many thanks for your valuable guidance in advance.

[wkhanna]

The lights in my house always dim momentarily when I power my 1090 on.
I do not have a separate circuit for my system, yet.

Do you run the amp through a power conditioner/surge protector, or straight from the outlet?

Does your unit still work OK otherwise?

Odd that this would just start happening on its own (assuming you have had the amp for while).

Have you added any appliances our other power-consuming devices or lighting lately?

(BTW, I merged both your posts so all the responses will be in one thread/location)

[mjb]

Check the thyristor and/or "spark killer" circuit.

[wkhanna]

Well Done, Mike!

Thanks!

[TAYFUR GUNAY]

Thank you Bill first merging my two messages,secondly for your reply and circuit. My unit unfortunately not working. I run my amp from the outlet, no any power condition or such in between. Last night we have gone one step forward, and discovered 20watt 10ohm large resistors found burned. As we go further and solve the problem I will share here with members.

[TAYFUR GUNAY]

The poblem was with the large "resistor" (20w/10ohm) and, in order to be safe side, "relay" on the surge absorber PCB have been replaced. Now the unit operates with no problem. For the concern of whom intrested I just shared... cheers.

[madmac]

That's very cool Tayfur that you have the electrical wherewithall to diagnose and fix a problem like that yourself!

Congrats !!

[wkhanna]

The poblem was with the large "resistor" (20w/10ohm) and, in order to be safe side, "relay" on the surge absorber PCB have been replaced. Now the unit operates with no problem. For the concern of whom intrested I just shared... cheers.

Sounds similar to an issue Dan (PewterTA) had.
His problem was the result of a power surge.

Glad you got it fixed!

You may be interested the mods Dan made to his & my 1090.
details found here:

http://www.htguide.com/forum/showthread.php?38853-RB-1090-injured-(&highlight=1090+mod